Eratosthenes - here are some of his mathematical creations:


Measuring the circumference of the earth contains some complicated concepts, particularly measurement of angles, but is also interesting because he was using what we would call a type of informal unit, the length of a stadium, for distance.

Eratosthenes lived from 276 to 195BC, dying at a very grand age of 82. He was notable as the third chief librarian of the Great Library of Alexandria, the center of science and learning in the ancient world.